42. Q. Why are eccentric rods made adjustable?
A. In order to change their length to make adjustment of the valve gear not as easily made in other ways.
43. Q. Why is it necessary to keep the cylinders free from water?
A. In order to avoid damaging valves and cylinders, to insure perfect lubrication and obtain the most efficient service from the locomotive.
44. Q. Where is the piston rod packing located? Where cylinder packing?
A. Piston rod packing is usually soft metallic rings located inside of a gland at the back end of cylinder and around the rod. Cylinder packing rings are usually cast iron, placed around the piston head and bearing against the walls of the cylinder.
45. Q. How are metallic packing rings on piston rods and valve stems held in place? What provisions are made for the uneven movements of the rod?
A. The packing rings fit into a vibrating cup or cone located inside the gland, being held therein by means of a spring as well as by the steam pressure. Provision is made for uneven movement of the rod by making the inside of the gland larger than the vibrating cup and using a ball-joint ring between the vibrating cup and gland.
46. Q. While running under steam and there is a failure of part of the locomotive which does not seem to prevent running at full speed, how would you proceed?
A. Keep the locomotive running if in your judgment it is safe. Try to ascertain what the injury is and be prepared at the next stop to do such work as the case demands, being careful to make the stop at such a place that the work can be done without interfering with the movements of main line trains.